Asyncio gather

#python   #asyncio  

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Table of Content

Asyncio gather

asyncio.gather() function to run multiple asynchronous operations.

gather(*aws, return_exceptions=False) -> Future[tuple[()]]

Simple Demo

The following example uses the asyncio.gather() to run two asynchronous operations and displays the results:

import asyncio

async def do_work(delay, work):
    await asyncio.sleep(delay)
    return work

async def main():
    a, b = await asyncio.gather(
        do_work(2, "hello"),
        do_work(2, "world")
    )


    print(f"{a}, {b}")
asyncio.run(main())

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Demo: task with exception

exception

import asyncio

async def do_exception(delay):
    await asyncio.sleep(delay)
    raise Exception("API failed")

async def do_work(delay, work):
    await asyncio.sleep(delay)
    return work

async def main():
    a, b = await asyncio.gather(
        do_work(2, "hello"),
        do_exception(1),
        return_exceptions=True
    )

    print(type(a))
    print(type(b))
    print(f"{a}, {b}")
asyncio.run(main())

<class 'str'>
<class 'Exception'>
hello, API failed

Set return_exceptions to True to allow errors to be returned as results.

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Reference

• Python asyncio.gather()